Primary time standards such as atomic clocks have traditionally been relatively large table top devices. For example, a physics package of a conventional atomic clock tends to be large and requires an expensive support system. Thus, efforts are under way to reduce the size of primary time standards such as by reducing the physics package of atomic clocks and other sensors which utilize cold atom clouds as the sensing element.
Making the physics package smaller has unique and complex challenges since the physics package requires multiple windows, minors, and a hermetic seal of non-magnetic materials. In conventional methods of manufacturing a physics package, a glass body is machined with multiple holes for placement of minors and windows on its exterior, and a plurality of angled borings that serve as light paths to trap, cool, and manipulate the cold atomic sample. A cavity evacuation structure or pumping port is attached to provide for initial vacuum evacuation of the physics package. The machining must leave enough internal structure to support building the physics package.
In general, an atomic clock operates by interrogating atoms with light beams from one or more lasers. The physics package defines a vacuum sealed chamber that holds the atoms that are interrogated. The atoms within the physics package are trapped within the volume such that the plurality of light paths intersect with the atoms from different angles.
Developing a small volume physics package which allows for large optical beams and added-flexibility of a multi-beam configuration is important to the development of high performance miniature atomic physics packages. However, smaller size requirements for atomic clocks is challenging current building techniques. The size reduction of atomic clocks affects their performance as the mirrors and windows shrink. Furthermore, the internal volume reduction adversely affects performance of the atomic clocks.